Lecture on Hypothenar Muscles

Overview

• Transition hand muscles: Muscles that originate and end in the hand.
• Intrinsic hand muscles: 3 groups:
  1. Thenar muscles (covered previously)
  2. Hypothenar muscles (little finger group, covered in this lecture)
  3. Middle hand muscles (to be covered next)

Components of Hypothenar Muscles

• Consist of 3 muscles (simpler than the thenar muscles with 4 muscles)
• Common aspects:
  • All require an abductor and a flexor
  • Origin mainly in the area of the carpal region on the ulnar side
  • Key bones: Pisiform, Hook of Hamate
  • Important ligaments: Pisohamate ligament, Pisometacarpal ligament

Muscle 1: Musculus Opponens Digiti Minimi

• Origin: Hamulus (hook) of Hamate and Flexor Retinaculum
• Insertion: Metacarpal V
• Function: Allows the small finger to oppose, mainly performing a combination of flexion, abduction, and rotation.

Muscle 2: Musculus Abductor Digiti Minimi

• Origin: Pisiform and tendon of Flexor Carpi Ulnaris
• Insertion: Base of the proximal phalanx of the small finger
• Function: Abducts the small finger (moves it laterally).

Muscle 3: Musculus Flexor Digiti Minimi

• Origin: Hamate and Flexor Retinaculum
• Insertion: Proximal phalanx base of the small finger
• Function: Flexes the proximal phalanx of the small finger.

Key Points

• Hypothenar muscles are simpler with only 3 muscles.
• Mainly located on the ulnar side of the hand.
• Important for movements of the small finger including flexion, abduction, and opposition.

Upcoming

• Next lecture will cover the middle hand muscles.