(The Study of Threes)
http://threesology.org
H.O.B. Note: the following was initially created from the information provided at Dr. McNulty's website which has an expressed date of 1997 as its inception, though the beginning of the compilation may have begun years before.
http://www.lumen.luc.edu/lumen/MedEd/GrossAnatomy/Threes.html
The structure of the human body is organized into groups of three with remarkable frequency. I have listed several examples of this tendency by region. This list does not include structures contributing to form the many "triangles" in the body.
If you know of any more, please let me know: --- John A. McNulty, Ph.D. ---
mailto:jmcnulty@lumc.edu
General
3 layers of skin: Epidermis- Dermis- Hypodermis
3 general venous circulations: Systemic- Pulmonary- Portal
Embryology
3 germ layers: Endoderm- Mesoderm- Ectoderm
3 divisions of somites: Sclerotome- Dermatome- Myotome
3 definitive kidneys: Pronephros- Mesonephros- Metanephros
3 derivatives of skull: Desmo/dermatocranium- Splanchno/viscerocranium- Chondrocranium
3 initial embryonic divisions of the brain: Prosencephalon- Mesencephalon- Rhombencephalon
Back
3 parts of the erector spinae m.: Iliocostalis- Longissimus- Spinalis
(each are divided again into 3 parts)
3 parts of the transversospinalis m.: Semispinalis m.- Multifidus m.- Rotator m.
3 coverings of the spinal cord: Dura mater- Arachnoid- Pia
3 spaces surrounding spinal cord: Epidural- Subdural- Subarachnoid
3 borders of the scapula: Medial (vertebral)- Lateral- Superior
3 angles of the scapula
Neck
3 parts of the axillary artery...
3rd part of axillary artery has 3 branches:
Subscapular- Anterior humeral circumflex- Posterior humeral circumflex
3 Brachial plexus trunks: Upper- Middle- Lower
3 posterior Brachial plexus divisions
3 anterior Brachial plexus divisions)
3 Brachial plexus cords:
(A) Lateral
(B) Medial
3 branches off medial cord: Medial brachial- Medial antebrachial- Medial pectoral
(C) Posterior
3 branches off posterior cord: Upper subscapular- Lower subscapular- Thoracodorsal
3 branches off the thyrocervical trunk: Transverse cervical- Suprascapular- Inferior thyroid
3 veins drain the thyroid gland:
- Superior (into internal jugular)
- Middle (into internal jugular)
- Inferior (into left brachiocephalic)
3 scalene muscles: Anterior- Middle- Posterior
3 muscles attach to spine of C2:
- Semispinalis cervicis
- Obliquus capitis inferior
- Rectus capitis posterior major
3 constrictor muscles: Superior- Middle- Inferior
3 parts of the pharynx: Nasopharynx- Oropharynx- Laryngeopharynx
3 parts to the hyoid bone: Body- Greater horn- Lesser horn
3 structures inside carotid sheath: Common carotid artery- Internal jugular vein- Vagus nerve
3 ganglia in sympathetic cervical chain: Superior (magnum)- Middle- Inferior (stellate)
Head
3 parts of the maxillary artery: Mandibular- Pterygoid- Pterygopalatine
3 divisions of the trigeminal nerve:
- V1 Ophthalmic... has 3 branches (Frontal- Nasociliary- Lacrimal
- V2 Maxillary
- V3 Mandibular
(has 3 parts) Undivided trunk- Anterior division- Posterior division
(has 3 branches) Auriculotemporal- Lingual inferior- Alveolar
3 cranial fossae: Anterior- Middle- Posterior
3 nuchal (nape of the neck) lines: Iinferior- Superior- Highest
3 layers to calvarium: Outer table- Diploe- Inner table
3 clinoid processes of the sphenoid bone: Anterior- Middle- Posterior
3 cranial nerves (C.N.) pass through jugular foramen: C.N. IX- C.N. X- C.N. XI
3 cranial nerves (C.N.) travel in the wall of the cavernous sinus: C.N. III- C.N. IV- C.N. V
3 cranial nerves (C.N.) carry parasympathetics to the head: C.N. III- C.N. VII- C.N. IX
3 nasal conchae: Superior- Middle- Inferior
3 principal components of the temporal bone: Squama- Petro/mastoid- Tympanic ring
3 bones of the upper jaw/palate: Premaxilla- Maxilla- Palatine
3 salivary glands: Parotid- Submaxillary- Sublingual
3 muscles innervated by 3 cranial nerves attach to the styloid process:
- Stylohyoid - C.N. VII
- Stylopharyngeus - C.N. IX
- Styloglossus - C.N. XII
3 layers in tympanic membrane [eardrum] (derived from 3 germ layers)
3 cranial nerves innervate the external tympanum: C.N. V- C.N. VII- C.N. X
3 middle ear bones: Incus- Malleus- Stapes
3 parts of the ear: Outer- Middle- Inner
3 semicircular canals (of the ear)
3 membranes of the cochlea: Reissner- Tectorial- Basilar
3 intrinsic muscles of the tongue: Longitudinal- Vertical- Transverse
3 muscles elevate the mandible: Masseter m.- Temporalis m.- Medial pterygoid m.
3 branches of the posterior auricular artery:
- Stylomastoid branch
- Auricular branch
- Occipital branch
3 branches of the ophthalmic nerve (VI): Nasociliary n.- Frontal n.- Lacrimal n.
3 superior alveolar nerves:
- Anterior superior alveolar nerve
- Middle superior alveolar nerve
- Posterior superior alveolar nerve
3 types of deciduous teeth: Incisors- Canine- Molars
3 layers of dentition: Enamal- Dentin- Pulp
3 general layers of the eye: Retinal- Choroidal/ciliary body- Scleral/corneal
3 color receptors in (eye) cone cells: Red- Blue- Yellow
3 nerves to the larynx:
- External laryngeal nerve
- Internal laryngeal nerve
- Recurrent laryngeal nerve
3 cerebral arteries: Anterior- Middle- Posterior
3 arteries supply the cerebellum:
- Superior cerebellar
- Anterior inferior cerebellar
- Posterior inferior cerebellar
Shoulder
3 muscles attach to coracoid process: Coracobrachialis- Pectoralis minor- Short head of biceps
3 parts of the axillary artery... (3rd part has 3 branches):
- Subscapular artery
- Anterior circumflex humeral artery
- Posterior circumflex humeral artery
3 muscles of the rotator cuff are rotators
3 glenohumeral ligaments: Superior- Middle- Inferior
Arm
3 muscles in anterior comparment: Biceps brachii- Coracobrachialis- Brachialis
3 heads of triceps brachii m.: Long- Lateral- Medial
3 muscles attach to greater tubercle of the humerus: Supraspinatus- Infraspinatus- Teres minor
3 parts of the ulnar collateral ligament of the elbow: Anterior- Posterior- Oblique
Forearm
3 muscles in deep anterior compartment:
- Flexor digitorum profundus
- Flexor pollicis longs
- Pronator quadratus
Hand
3 muscles in thenar eminence:
- Opponens pollicis
- Flexor pollicis brevis
- Abductor pollicis brevis
3 muscles in hypothenar compartment:
- Flexor digiti minimi
- Abductor digiti minimi
- Opponens digiti minimi
3 phalanges in fingers: Proximal- Middle- Distal
3 palmer interossei
Thorax
3 compartments: Mediastinum- Left pleural cavity- Right pleural cavity
3 branches off the aortic arch:
- Brachiocephalic artery
- Left common carotid artery
- Left subclavian artery
3 parts of the aorta: Ascending- Arch- Descending
3 principal surfaces of the pleura: Costal- Diaphragmatic- Mediastinal
(the cupola is the superior extension)
3 lobes of the right lung: Superior- Middle- Inferior
3 bronchopulmonary segments of the upper right lobe: Apical- Posterior- Anterior
3 muscles of interthoracic wall:
- External intercostal
- Internal intercostal
- Intercostalis intimus
3 false ribs on each side
3 cusps of the semilunar aortic and pulmonary valves of the heart
3 cusps of the tricuspid (heart) valve
3 main arteries of the heart: Circumflex- Anterior interventricular- Right coronary
3 splanchnic nerves: Greater- Lesser- Least
Abdomen
3 folds in anterior abdominal wall:
- Median (obliterated urachus)
- Medial (obliterated umbilical a.)
- Lateral (inferior epigastric a.)
3 muscles contribute to linea semilunaris/rectus abdominus aponeurosis:
- Internal oblique
- External oblique
- Transversus abdominus
3 openings in diaphragm: Aortic- Esophageal- Inferior vena cava
3 arcuate ligaments of diaphragm:
- Median over aorta
- Medial over psoas major m.
- Lateral over quadratus lumborum m.
3 parts of the stomach: Fundus- Body- Pylorus
3 smooth muscle layers of the stomach: Oblique- Longitudinal- Circular
3 unpaired branches of the abdominal aorta:
- Celiac a.
- Superior mesenteric a.
- Inferior mesenteric a.
3 brances of celiac a.: Left gastric a.- Splenic a.- Common hepatic a.
3 brancheds of common hepatic a.: Right gastric a.- Proper hepatic a.- Gastroduodenal a.
3 arterial branches supply adrenal glands: Inferior phrenic- Aorta- Renal
3 structures lie within porta hepatis: Proper hepatic a.- Portal vein- Common bile duct
3 principal veins contribute to the portal vein:
- Splenic vein
- Superior mesenteric vein
- Inferior mesenteric vein
3 parts of the small intestine: Duodenum- Jejunum- Ileum
3 parts of large intestine: Ascending- Transverse- Descending
3 tenia (band-like structure) of large intestine
3 coverings of the spermatic cord:
- External spermatic fascia
- Cremasteric fascia
- Internal spermatic fascia
3 vessels in the umbilical cord: Umbilical vein and 2 umbilical arteries
Pelvis and Perineum
3 bones in os coxae: Pubis- Ilium- Ischium
3 parts of the pubis: Body- Superior ramus- Inferior ramus
3 foramina in the pelvis:
- Obturator foramen
- Greater ischiadic foramen
- Lesser ischiadic foramen
3 gluteus muscles: Gluteus maximus- Gluteus medius- Gluteus minimus
3 rectal arteries:
- Superior rectal from inferior mesenteric artery
- Middle rectal from internal iliac artery
- Inferior rectal from internal pudendal artery
3 branches of the posterior division of internal iliac artery:
- Iliolumbar
- Lateral sacral
- Superior gluteal
3 openings in the urinary bladder: Left ureter- Right ureter- Urethra
3 parts of the urethra: Prostatic- Membranous- Spongy
3 parts of the uterus: Fundus- Body- Cervix
3 erectile compartments of the penis:
- Corpus spongiosum
- Left corpus cavernosum
- Right corpus cavernosum
3 muscles in superficial perineal pouch:
- Bulbospongiosus
- Ischiocavernosus
- Superficial transverse perineus
3 arteries supply the rectum:
- Superior rectal (from inferior mesenteric)
- Middle rectal (from internal iliac)
- Inferior rectal (from internal pudendal)
3 valves in the rectum: Superior- Middle- Inferior
Gluteus
3 gluteal muscles: Gluteus maximus- Gluteus medius- Gluteus minimus
3 muscles innervated by superior gluteal n.:
- Gluteus medius
- Gluteus minimus
- Tensor fascia lata
Thigh
3 hamstring muscles: Biceps femoris- Semitendinosus- Semimembranosus
3 compartments in the femoral sheath
3 muscular compartments of the thigh: Anterior- Medial- Posterior
3 branches of the lateral femoral circumflex a.:
- Descending branch
- Transverse branch
- Ascending branch
3 muscles contribute to the pes anserinus: Sartorius- Semitendinosus- Gracilis
Leg
3 compartments in the leg... (3 muscles in anterior compartment:)
- Tibialis anterior
- Extensor digitorum
- Extensor hallucis
- Anterior tibial artery
- Posterior tibial artery
- Peroneal artery
Foot
3 cuneiform bones: Medial- Intermediate- Lateral
3 phalanges in toes: Proximal- Middle- Distal
3 plantar interossei (related to the sole of the foot)
Miscellaneous
3 exams in the course
http://www.lumen.luc.edu/lumen/MedEd/GrossAnatomy/Threes.html
H.O.B. notes:
Dr. McNulty's comment about the many "Triangles" in the human body is a reference easily passed over by many readers. Some think of a triangle in terms only of a geometric representation of the "three," but it is more than this when be think in terms of what may have influenced the many three-patterned structures in the human body. In so doing, we need to account not only for a pattern-of-three serial event (1 + 1 +1) that could very well develop into a 1 and then 2 and then 3, but one that also exhibits a triangular form that would have impressed this form upon our physiology/anatomy. However, I have also found the existence of examples exhibiting a 1 from 3, 3 into 1, or 3 to 1 (1 to 3) characterization, thus requiring that which influenced (influences) "threes" in our anatomical structure, to also have a triangle and 3 -to- 1 pattern.
At present, the only thing that I can see having existed since before and during (and quite possibly long after) the development of the human species, is the Sun. It has existed long before the development of life on Earth and has all three aforementioned characteristics:
- It has three "intense" moments called dawn- noon- dusk.
- The path of the Sun is triangular as identified by time-elapsed photography.
- The three moments are "fusing" together producing a 3 into 1 condition as the Earth's rate of rotation slows and the Sun expands as it decays towards its eventual burnout.
H.O.B. note: Here's another list of Anatomical 3's I came across posted by a Dr. Moongarg. I have arranged section headings in alphabetical order.
Study Temple: List of threes in anatomy
http://www.studytemple.com/forum/aipget-mcq-aiims/8303-list-three-s-anatomy.html
 |
Dr.MoonGarg LION Post Graduate |
| Posting date: 03-11-2009 11:28 AM | |
General 3 body planes - frontal, sagittal, transverse 3 layers of skin - epidermis, dermis, hypodermis 3 general venous circulations - systemic, pulmonary, portal Embryology 3 germ layers - endoderm mesoderm ectoderm 3 divisions of somites - sclerotome dermatome myotome 3 definitive kidneys - pronephros mesonephros metanephros 3 derivatives of skull - desmo/dermatocranium splanchno/viscerocranium chondrocranium 3 initial embryonic divisions of the brain - prosencephalon mesencephalon rhombencephalon Back 3 parts of the erector spinae m. - iliocostalis longissimus spinalis (each are divided again into 3 parts) 3 parts of the transversospinalis m. - semispinalis m. multifidus m. rotator m. 3 coverings of the spinal cord - dura mater arachnoid pia 3 spaces surrounding spinal cord - epidural subdural subarachnoid 3 borders of the scapula - medial (vertebral) lateral superior 3 angles of the scapula Neck 3 parts of the axillary artery 3rd part has 3 branches- subscapular anterior humeral circumflex posterior humeral circumflex Brachial plexus 3 trunks - upper middle lower 3 posterior divisions 3 anterior divisions 3 cords - 1. lateral 2. medial 3 branches off medial cord - medial brachial medial antebrachial medial pectoral 3. posterior 3 branches off posterior cord - upper subscapular lower subscapular thoracodorsal 3 branches off the thyrocervical trunk - transverse cervical suprascapular inferior thyroid 3 veins drain the thyroid gland - superior (into internal jugular) middle (into internal jugular) inferior (into left brachiocephalic) 3 scalene muscles - anterior middle posterior 3 muscles attach to spine of C2 - semispinalis cervicis obliquus capitis inferior rectus capitis posterior major 3 constrictor muscles - superior middle inferior 3 parts of the pharynx - nasopharynx oropharynx laryngeopharynx 3 parts to the hyoid bone - body greater horn lesser horn 3 structures inside carotid sheath - common carotid artery internal jugular vein vagus nerve 3 ganglia in sympathetic cervical chain - superior (magnum) middle inferior (stellate) Head 3 parts of the maxillary artery - mandibular pterygoid pterygopalatine 3 divisions of the trigeminal n. - V1 (ophthalmic, has 3 branches) - frontal nasociliary lacrimal V2 - maxillary V3 - mandibular (has 3 parts) - a. undivided trunk b. anterior division c. posterior division (has 3 branches) - a. auriculotemporal b. lingual c. inferior alveolar 3 cranial fossae- anterior middle posterior 3 nuchal lines - inferior superior highest 3 layers to calvarium - outer table diploe inner table 3 clinoid processes of the sphenoid bone - anterior middle posterior 3 cranial nerves pass through jugular foramen - C.N. IX C.N. X C.N. XI 3 Cranial Nerves travel in the wall of the cavernous sinus - C.N. III C.N. IV C.N. V 3 Cranial Nerves carry parasympathetics to the head - C.N. III C.N. VII C.N. IX 3 nasal conchae - superior middle inferior 3 principal components of the temporal bone - squama petro/mastoid tympanic ring 3 bones of the upper jaw/palate - premaxilla maxilla palatine
H.O.B. note: At this juncture, it is of value to note that we humans have a 1st, 2nd and 3rd molar designation as well as the 3rd molars being designated the wisdom teeth. However, it is of notable interest to provide an illustration of the number of teeth in different animals:
3 salivary glands - parotid submaxillary sublingual 3 muscles innervated by 3 cranial nerves attach to the styloid process - stylohyoid - C.N. VII stylopharyngeus - C.N. IX styloglossus - C.N. XII 3 layers in tympanic membrane (derived from 3 germ layers) 3 Cranial Nerves innervate the external tympanum - C.N. V C.N. VII C.N. X 3 middle ear bones - incus malleus stapes 3 parts of the ear - outer middle inner 3 semicircular canals 3 membranes of the cochlea - Reissner Tectorial Basilar
H.O.B. note: With respect to hearing, speech and grammar, see the following link:
3 intrinsic muscles of the tongue - longitudinal vertical transverse 3 muscles elevate the mandible - masseter m. temporalis m. medial pterygoid m. 3 branches of the posterior auricular artery - stylomastoid branch auricular branch occipital branch 3 branches of the ophthalmic nerve (VI) - nasociliary n. frontal n. lacrimal n. 3 superior alveolar nerves - anterior superior alveolar n. middle superior alveolar n. posterior superior alveolar n. 3 types of deciduous teeth - incisors canine molars 3 layers of dentition- enamal dentin pulp 3 general layers of the eye - retinal choroidal/ciliary body scleral/corneal 3 color receptors in cone cells - red blue yellow 3 nerves to the larynx - external laryngeal n. internal laryngeal n. recurrent laryngeal n. 3 cerebral arteries - anterior middle posterior 3 arteries supply the cerebellum - superior cerebellar anterior inferior cerebellar posterior inferior cerebellar Shoulder 3 muscles attach to coracoid process - coracobrachialis pectoralis minor short head of biceps 3 parts of the axillary a.; 3rd part has 3 branches - subscapular a. anterior circumflex humeral a. posterior circumflex humeral a 3 muscles of the rotator cuff are rotators 3 glenohumeral ligaments - superior middle inferior Arm 3 muscles in anterior comparment - biceps brachii coracobrachialis brachialis 3 heads of triceps brachii m. - long lateral medial 3 muscles attach to greater tubercle of the humerus - supraspinatus infraspinatus teres minor 3 parts of the ulnar collateral ligament of the elbow - anterior posterior oblique Forearm 3 muscles in deep anterior compartment - flexor digitorum profundus flexor pollicis longs pronator quadratus Hand 3 muscles in thenar eminence - opponens pollicis flexor pollicis brevis abductor pollicis brevis 3 muscles in hypothenar compartment - flexor digiti minimi abductor digiti minimi opponens digiti minimi 3 phalanges in fingers - proximal middle distal 3 palmer interossei Thorax 3 compartments - mediastinum left pleural cavity right pleural cavity 3 branches off the aortic arch - brachiocephalic a. left common carotid a. left subclavian a. 3 parts of the aorta - ascending arch descending 3 principal surfaces of the pleura- costal diaphragmatic mediastinal *the cupola is the superior extension 3 lobes of the right lung - superior middle inferior
H.O.B. note: 3 lobes on the right, 2 on the left. 3 (tricuspid) heart valves on the right, 2 (mitral/bicuspid) valves on the left. And thinking in terms of a stroke, where the left hemisphere brain is affected, the right side is affected and vice versa. Attributes of the left brain hemisphere are "three" organized while attributes aligned with the right hemisphere are "two" organized. See the following link for an illustration of this:
3 bronchopulmonary segments of the upper right lobe - apical posterior anterior 3 muscles of interthoracic wall - external intercostal internal intercostal intercostalis intimus 3 false ribs on each side 3 cusps of the semilunar aortic and pulmonary valves of the heart 3 cusps of the tricuspid valve 3 main arteries of the heart - circumflex anterior interventricular right coronary 3 splanchnic nerves - greater lesser least Abdomen 3 folds in anterior abdominal wall - median (obliterated urachus) medial (obliterated umbilical a.) lateral (inferior epigastric a.) 3 muscles contribute to linea semilunaris/rectus abdominus aponeurosis - internal oblique external oblique transversus abdominus 3 openings in diaphragm - aortic esophageal inferior vena cava 3 arcuate ligaments of diaphragm - median over aorta medial over psoas major m. lateral over quadratus lumborum m. 3 parts of the stomach - fundus body pylorus 3 smooth muscle layers of the stomach - oblique longitudinal circular 3 unpaired branches of the abdominal aorta - celiac a. superior mesenteric a. inferior mesenteric a. 3 branches of celiac a. - left gastric a. splenic a. common hepatic a. 3 branches of common hepatic a. - right gastric a. proper hepatic a. gastroduodenal a. 3 arterial branches supply adrenal glands - inferior phrenic aorta renal 3 structures lie within porta hepatis - proper hepatic a. portal vein common bile duct 3 principal veins contribute to the portal vein - splenic v. superior mesenteric v. inferior mesenteric v. 3 parts of the small intestine - duodenum jejunum ileum 3 parts of large intestine - ascending transverse descending 3 tenia of large intestine 3 coverings of the spermatic cord - external spermatic fascia cremasteric fascia internal spermatic fascia 3 vessels in the umbilical cord - 1 umbilical vein 2 umbilical arteries Pelvis and Perineum 3 bones in os coxae - pubis ilium ischium 3 parts of the pubis - body superior ramus inferior ramus 3 foramina in the pelvis - obturator foramen greater ischiadic foramen lesser ischiadic foramen 3 gluteus muscles - gluteus maximus gluteus medius gluteus minimus 3 rectal arteries - superior rectal from inferior mesenteric a. middle rectal from internal iliac a. inferior rectal from internal pudendal a. 3 branches of the posterior division of internal iliac a. - iliolumbar lateral sacral superior gluteal 3 openings in the urinary bladder - left ureter right ureter urethra 3 parts of the urethra - prostatic membranous spongy 3 parts of the uterus - fundus body cervix 3 erectile compartments of the penis - corpus spongiosum left corpus cavernosum right corpus cavernosum 3 muscles in superficial perineal pouch - bulbospongiosus ischiocavernosus superficial transverse perineus 3 arteries supply the rectum - superior rectal (from inferior mesenteric) middle rectal (from internal iliac) inferior rectal (from internal pudendal) 3 valves in the rectum - superior, middle, inferior Gluteus 3 gluteal muscles - gluteus maximus, gluteus medius, gluteus minimus 3 muscles innervated by superior gluteal n. - gluteus medius gluteus minimus tensor fascia lata Thigh 3 hamstring muscles - biceps femoris semitendinosus semimembranosus 3 compartments in the femoral sheath 3 muscular compartments of the thigh - anterior medial posterior 3 branches of the lateral femoral circumflex a. - descending branch transverse branch ascending branch 3 muscles contribute to the pes anserinus - sartorius semitendinosus gracilis Leg 3 compartments in the leg 3 muscles in anterior compartment - tibialis anterior extensor digitorum extensor hallucis 3 branches of the peroneal artery in the leg - anterior tibial a. posterior tibial a. peroneal a. 3 peroneal muscles in the leg - peroneus longus m. peroneus brevis m. peroneus tertius m. 3 muscles that comprise the triceps surae - grastrocnemius m. soleus m. plantaris m. 3 muscles in the deep posterior compartment - tibialis posterioris m. flexor hallucis longus m. flexor digitorum longus m. Foot 3 cuneiform bones - medial, intermediate, lateral 3 phalanges in toes - proximal, middle, distal 3 plantar interossei 3 described arches - medial, lateral, transverse
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Herb O. Buckland
herbobuckland@hotmail.com