GENERAL INFORMATION
The intermediate muscles of the hand are a group of muscles located between the thenar and hypothenar muscles. They play a role in controlling the movement and stability of the fingers and contribute to fine motor skills and precision movements of the hand.
ORIGIN
The origin of the intermediate muscles varies depending on the specific muscle within the group. These muscles may originate from the metacarpal bones or the interosseous membrane, a fibrous tissue that spans between the metacarpal bones.
INSERTION POINT
The insertion points of the intermediate muscles are on the proximal phalanges and the extensor expansion of the fingers. They attach near the metacarpophalangeal joints and extend to the distal phalanges of the fingers.
MAJOR ARTERIES
The intermediate muscles receive their blood supply from branches of the radial and ulnar arteries, which provide oxygenated blood to the muscles for their proper function.
NEURAL INNERVATION
The deep branch of the ulnar nerve primarily innervates the intermediate muscles. This nerve arises from the brachial plexus and provides both sensory and motor innervation to the muscles.
TRIGGER POINT
Trigger points may develop in the intermediate muscles due to muscle tension, overuse, or injury. These trigger points can cause localised pain, tenderness, or referred pain in the hand and fingers.
CONCENTRIC FUNCTION
The concentric function of the intermediate muscles involves the contraction of the muscle fibres, resulting in the flexion or extension of the fingers. This contraction allows for precise control and movement of the fingers during activities such as gripping, writing, or playing musical instruments.
ECCENTRIC FUNCTION
The eccentric function of the intermediate muscles occurs when the muscle fibres lengthen under tension. This function assists in controlled relaxation and return to the neutral position of the fingers.
ISOMETRIC FUNCTION
The isometric function of the intermediate muscles involves contracting and generating tension without changing the length of the muscles. This function helps maintain stability and support in the fingers during various hand movements.
RELATED MUSCLE SCIENTIFIC NAMES
The specific muscles within the intermediate group include:
- Dorsal interossei muscles: These muscles are responsible for abducting the fingers (spreading them apart).
- Palmar interossei muscles: These muscles adduct the fingers (bringing them together).
- Lumbrical muscles: These muscles flex the metacarpophalangeal joints and extend the interphalangeal joints of the fingers.
ANTAGONIST MUSCLES
The antagonist muscles to the intermediate muscles include the muscles of the thenar and hypothenar groups. These muscles work in opposition to the intermediate muscles, allowing for coordinated movements and balance of the hand and fingers.
COMMON INJURIES
- Strain or sprain: Overexertion or sudden traumatic events can lead to strain or sprain in the intermediate muscles.
- Tendinitis: Inflammation or irritation of the tendons of the intermediate muscles due to repetitive use or strain.
EXERCISES
- Finger flexion and extension exercises: Perform exercises that involve flexing and extending the fingers against resistance, such as using therapy putty or hand grip strengtheners.
- Finger abduction and adduction exercises: Perform exercises that involve spreading the fingers apart and bringing them together, targeting the dorsal and palmar interossei muscles.
- Grip strengthening exercises: Perform exercises that target overall grip strength, indirectly strengthening the intermediate muscles.
- Lumbrical strengthening exercises: Use rubber bands around the fingers to perform extension and flexion, specifically targeting the lumbrical muscles.
- Therapy ball squeezes: Squeeze a therapy ball to enhance overall hand strength, including the intermediate muscles.
STRETCHES
- Finger stretches: Perform stretches that involve extending and stretching the fingers, both individually and collectively.
- Hand and wrist stretch: Perform stretches that target the flexibility and mobility of the hand and wrist, including stretches for the fingers and interossei muscles.
- Lumbrical stretches: Bend the fingers at the metacarpophalangeal joints while keeping the interphalangeal joints straight to stretch the lumbrical muscles.
- Finger abduction stretch: Use the other hand to spread the fingers apart, targeting the interossei muscles gently.
- Palmar stretch: Place the palm flat on a table and gently press down to stretch the palmar interossei muscles.