Final answer:
Injury to the axillary nerve can cause weakness or paralysis of certain shoulder muscles and sensory deficits in the shoulder and upper arm.
Step-by-step explanation:
The motor deficits seen with injury to the axillary nerve can include weakness or paralysis of the deltoid muscle and teres minor muscle. This can result in difficulty in lifting the arm or performing certain movements involving the shoulder. Sensory deficits such as numbness or decreased sensation in the shoulder and upper arm may also be observed.
An injury to the axillary nerve can be caused by trauma, such as shoulder dislocation or fracture, or compression of the nerve. The diagnosis is usually made through physical examination and sometimes imaging tests to evaluate the extent of the injury.