Changes

===Proximal Interphalangeal (Pastern) Joint===

===Proximal Interphalangeal (Pastern) Joint===

The pastern joint allows flexion and extension movements. The palmar border of the middle phalanx has a complementary fibrocartilage that extends the proximal articular surface of the middle phalanx. It is sometimes called the middle scutum as it provides a gliding surface for the deep digital flexor. The joint capsule is simple and attaches by the articular margins of the two phalanges. The  '''collateral ligaments''' connect the distal end of the proximal phalanx to the proximal end of the middle phalanx. They lie in a vertical direction rather than along the bone axis. The fibres of the '''collateral sesamoid ligaments''' of the distal interphalangeal joint run with it, attach to the middle phalanx and then continue on to their distal attachments. The '''palmar ligaments''' connect the palmar aspect of the distal half of the proximal phalanx to the complementary fibrocartilage of the middle phalanx. These restrict dorsiflexion of the joint. A '''proximal digital annular ligament''' wraps around the superficial surface of the flexor tendons and their sheaths at the level of the proximal phalanx. There is a distal one also exists that is attached to the proximal phalanx, it is superficially associated with the digital cushion and is connected to the ergot by the thin fibrous '''ligament of the ergot'''.

The pastern joint, between the trochlea of the proximal phalanx and the proximal end of the second phalanx, allows flexion and extension movements. The palmar border of the middle phalanx has a complementary fibrocartilage that extends the proximal articular surface of the middle phalanx. It is sometimes called the middle scutum as it provides a gliding surface for the deep digital flexor tendon. The joint capsule is simple and attaches by the articular margins of the two phalanges; blending with the common digital extensor tendon dorsally, the collateral ligaments lateral and medially and the straight sesamoidean ligament on the palmar aspect.

 

The  '''collateral ligaments''' connect the distal end of the proximal phalanx to the proximal end of the middle phalanx. They lie in a vertical direction rather than along the bone axis. The fibres of the '''collateral sesamoid ligaments''' of the distal interphalangeal joint run with it, attach to the middle phalanx and then continue on to their distal attachments. The '''palmar ligaments''' connect the palmar aspect of the distal half of the proximal phalanx to the complementary fibrocartilage of the middle phalanx. These restrict dorsiflexion of the joint. A '''proximal digital annular ligament''' wraps around the superficial surface of the flexor tendons and their sheaths at the level of the proximal phalanx. There is a distal one also exists that is attached to the proximal phalanx, it is superficially associated with the digital cushion and is connected to the ergot by the thin fibrous '''ligament of the ergot'''.

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