Free part of upper limb
The free limbs of amphibians, reptiles, and mammals have the same basic structure through the forelimbs and hindlimbs. In other words, they are homologous. As a rule, the fingers are pentadactylous.
The homology between the forelimb and hindlimb is shown in the following table.
| forelimb | hindlimb |
stylopodium | Humerus | Femur |
zeugopodium | Radius Ulna | Tibia Fibula |
autopodium basipodium metapodium acropodium | carpus metacarpus phalanges | tarsus metatarsus phalanges |
When upright bipedal locomotion was acquired in the course of human evolution, the upper limb was freed from its role of supporting and propelling body weight. Such homology (in a broad sense) between the upper and lower limbs is not limited to the skeletal system, but is also seen in the muscular and vascular systems. One way of practicing osteology is to compare the upper and lower limbs.
The ratio of the length of each leg has some relationship to the animal's life type.:
In running terrestrial quadrupeds, stylopodium < zeugopodium; in heavy terrestrial quadrupeds, stylopodium > zeugopodium; in aquatic animals, stylopodium > autopodium.
- 1. Humerus
- ・Distinguish Head (1-1) ,Shaft (Body) of humerus (1-2),and Condyle of humerus(1-3).
- 1-1. Upper end part
- ・Head (2) ---- Anatomical neck (3)
- Touch it with a living body. Don't confuse it with acromion.
- Shoulder (Glenohumeral) joint ;Possible movements are?
- What about ligaments?
- ・Greater tubercle(Crest of greater tubercle)(4);What will attache?
- ・Lesser tubercle(Crest of lesser tubercle)
(5);What will attache?
- ・Intertubercular sulcus, bicipital groove (6);What runs?
- 1-2. Body part
- ・Surgical neck (7)
- ・Shaft of humerus;The cross-sectional shape is?
- ・Deltoid tuberocity (8);What will attach?
- ・Radial groove (9);What and how it runs?
- 1-3. Lower end part
- ・Lateral epicondyle (10-1),Medial epicondyle (10-2)
- Touch it in your body (watch out for the ulnar nerve!).
- What will attach at each epicondyle?
- What is Hueter's line? What is its clinical significance?
- ・Trochlea of humerus (11);Shaped like a sewing machine spool
- How big is it?
- ---- Humero-ulnar joint (12);The axis of motion is?
- ・Capitulum of humerus (13);Hemispherical in shape
- How big is it?
- ---- Humeroradial joint (14);The axis of motion is?
- ・Oecranon fossa (15);How big is it?
- Depth?
- What fits in?
- ・Cronoid fossa (16);How big is it?
- Depth?
- What fits in?
- ・Supratrochlear foramen (17);Were there any? (10% of Japanese males and 20% of Japanese females)
- 2.Radius
- ・ The form is?
- Radius means spokes of a wheel. The Japanese word for this bone means bending wood or the oar of a boat with a sagged shape.
- ・How about the size of the upper and lower ends?
- ・左The distinction between left and right is?
- ・How about front/rear curvatures?
- 2-1. Upper (proximal) end
- ・Head (18);Shape is like the grip end of a baseball bat.
- ・Articular facet ---- Humeroradial joint
- ・Articular circumference (19) ---- Proximal radio-ulnar joint (20)
- 2-2. Body part
- ・Radial tuberocity (21);Which muscle attaches?
- 2-3. Lower(distal)end
- ・Radial styloid process (22);Touch it with a living body
- ・Carpal articular surface of radius (23)---- Wrist joint (24)
- The composition and movement of this joint is?
- ・Ulnar notch (25);It resides in the radius, not in the ulna!
- (ulnar is an adjective, not possessive!)
- ---- Distal radio-ulnar joint (26);Movement is?
- 3. Ulna
- ・What is the size of the upper and lower ends?
- ・How about the distinction between left and right?
- 3-1. Upper end
- ・Trochlear notch (27) ---- Humero-ulnar joint (28)
- ・Olecranon (29);Touch it with a living body.
- ・Radial notch of ulna (30);It is present in the ulna not in the radius!
- (radial is also an adjective, not possessive!)
- ----> Proximal radio-ulnar joint (31); Movement is?
- ・Coronoid process (32);Where to fit in?
- 3-2. Lower end
- ・Head of ulna (33)
- The ulnar head is at the lower end!
- ・Ulnar styloid process (34)Can you touch it in your body?
- 4. Bones of hand
- The ossification state of hand-wrist bones, including the radius and ulna, can be observed radiographically to determine the maturity of the bones. There are two methods to determine maturity: comparing with the standard atlas method (atlas method: Greulich & Pyle's Atlas) and giving a maturity score (score method: TW3 method).
The position and interrelationship of the bones of the bones of the hand are shown in the schematic diagram.
- ・Midcarpal joint (35)
- ・Intercarpal joints (36);Does it move?
- ・Carpometacarpal joints (37)
- ・Intermetacarpal joints (38)
- ・Metacarpals (39)
- ・Phalanges
- Proximal phalanx (40-1),Middle phalanx (40-2),Distal phalanx (40-3)
- brachymesophalangia 5 (
BMP5) ---- Down's syndrome
- Metacarpophalangeal joints (41)
- Interphalangeal joints of hand (42)
- DIP joint (distal interphalangeal joint)
- PIP joint (proximal interphalangeal joint)
- ・Sesamoid bones(Open sesame!)
The homology of the carpals and tarsals, in terms of embryology, is considered as follows.
Hand | Foot |
Scaphoid bone | Navicular bone |
Lunate bone | Talus (a part) * |
Triquetrum bone | Calcaneus (a part) ** |
Pisiform bone | -------- |
Trapezium bone | Medial cuneiform bone |
Trapezoid bone | Intermediate cuneiform bone |
Capitate bone | Lateral cuneiform bone |
Hamate bone | Cuboid bone |
- * The rest are derived from tibiale and intermedium; ** the rest are derived from fibulare.
- Cihak, R. (1972) Ontogenesis of the skeleton and intrinsic muscles of the human hand and foot. Ergebnisse der Anatomie und Entwicklungsgeschichte, 46-1.
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- ・The ratio of metacarpal (metatarsal) and proximal phalanx lengths increases with the relative length of the metacarpals (metatarsals) as the locomotion pattern of the animal shiffts from plantar to phalangeal to hoofed.