3rd Metacarpal bone

Authors

Affiliations

Nate Yomogida, PT, DPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, PT, DPT

Doctor of Physical Therapy

B.A. in Neuroscience

Figure 1: Bones of the left hand (Anterior surface)¹

Figure 2: Bones of the left hand (posterior surface)¹

Figure 3: Plan of ossification of the hand¹

Figure 4: 3rd metacarpal (left)¹

Muscular attachments

Table 1: Muscles inserting on the 3rd Metacarpal bone

Muscle	Origin	Insertion	Innervation	Action
Extensor carpi radialis brevis	Lateral epicondyle of Humerus	3rd metacarpal base	Radial n. C7 - C8	Elbow: Weak flexion Wrist: Extension, Radial deviation
Flexor carpi radialis	Medial epicondyle	Base of 2nd Metacarpal (Sometimes base of 3rd Met)	Median n. C6 - C7	Wrist: Flexion, Radial deviation

Table 2: Muscles originating from the 3rd Metacarpal bone

Muscle	Origin	Insertion	Innervation	Action
2nd Dorsal interossei (hand)	2-3rd MCP adjacent sides	3rd dorsal digital expansion 3rd Proximal Phalanx (radial border)	Ulnar n. C8 - T1	3rd digit: MCP Flexion, PIP & DIP Extension & Abduction
3rd Dorsal interossei (hand)	3-4th MCP adjacent sides	4th dorsal digital expansion 4th Proximal Phalanx (radial border)	Ulnar n. C8 - T1	4th digit: MCP Flexion, PIP & DIP Extension & Abduction
Adductor pollicis	3rd MCP (plantar surface) Capitate 2-3rd metacarpal base	Base of 1st proximal phalanx (ulnar sesamoid)	Ulnar n. C8 - T1	CMC: Adduction 1st MCP: Flexion

References

1.

Gray H. Anatomy of the Human Body. 20th ed. (Lewis WH, ed.). Lea & Febiger; 1918. https://www.bartleby.com/107/