Demonstrate an awareness of the functional adaptations needed for prehension when underlying systems have been altered.

The hand is an extremely complex and intricate structure, consisting of numerous bones, muscles, ligaments, and nerves. It is also capable of a very diverse set of movements. The hands are used for a variety of purposes, including grasping, holding, pushing and pulling, as well as fine motor skills such as writing and typing (Kalsi-Ryan et al., 2020). The functions that depend on the use of the hand can be subdivided into two categories: prehension (the ability to grasp objects) and manipulation (the ability to move objects).

Prehension refers to the act of grasping, holding or manipulating objects, and is an important component of human hand function (Kalsi-Ryan et al., 2020). The ability to prehend objects is dependent upon a number of factors, including the size and shape of the object, the strength of the grasp, and fine motor coordination. The brain must also be able to interpret the sensory information received from receptors in the hand in order for prehension to occur effectively.

The functional adaptations needed for prehension when underlying systems have been altered include:

1) The ability to understand how objects are grasped depends on a number of factors including their size and shape as well as their weight and texture. The system used to detect shape and size involves visual acuity, posture and muscle strength. This system can be affected by neurological conditions such as stroke or Parkinson's disease which may result in poor vision or tremors that impair balance and coordination.

2) The ability to hold an object depends on muscle strength, particularly if it is heavy or bulky. If there is weakness due to neurological conditions such as stroke or Parkinson's disease then this could affect how securely an object can be held between two hands or fingers during prehension activities such as grasping food items or lifting objects off a shelf without dropping them.

References
Kalsi-Ryan, S., Riehm, L. E., Tetreault, L., Martin, A. R., Teoderascu, F., Massicotte, E., ... & Fehlings, M. G. (2020). Characteristics of upper limb impairment related to degenerative cervical myelopathy: Development of a sensitive hand assessment (graded redefined assessment of strength, sensibility, and prehension version myelopathy). Neurosurgery, 86(3), E292-E299.