Oblique Head of Adductor Pollicis

Origin

The oblique head of adductor pollicis muscle originates from the:

- palmar aspect of capitate bone;

- palmar aspect of the base of second metacarpal bone;

- Palmar aspect of the base of third metacarpal bone.

Insertion

The muscle bellies of the oblique and transverse heads of adductor pollicis travel inferolaterally and converge to a single tendon. This tendon contains a sesamoid bone and inserts onto the medial aspect of the base of the proximal phalanx of thumb.

Key Features & Anatomical Relations

The adductor pollicis muscle is found in the adductor compartment of the hand. It is a fan-shaped skeletal muscle and is composed of two heads, which are named based on the orientation of their muscle fibers:

- oblique head of adductor pollicis muscle;

- transverse head of adductor pollicis muscle.

The adductor pollicis muscle is located:

- anterior to the second metacarpal bone, and the first dorsal interosseous muscle of hand;

- posterior to the first lumbrical muscle of hand, and the tendons of the flexor digitorum profundus and superficialis that go to the index finger;

- medial to the flexor pollicis brevis and opponens pollicis muscles.

The deep palmar arch and the deep branch of ulnar nerve travel between the oblique and transverse heads of adductor pollicis muscle.

Actions & Testing

The adductor pollicis muscle adducts the first metacarpal bone (of thumb) at the first carpometacarpal joint. It can be tested by adducting the first metacarpal (of thumb) at its carpometacarpal joint against resistance (Standring, 2016).

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.