Structure and Origin of Deep Temporal Nerves:
- Arise from the mandibular nerve (CN V)
- Usually arise from the anterior division of the mandibular nerve
- The anterior deep temporal nerve may arise from the buccal nerve
- The posterior deep temporal nerve may arise from the masseteric nerve
- Pass superior to the superior border of the lateral pterygoid muscle
- Ascend to the temporal fossa
- Enter the deep surface of the temporalis muscle

Motor Innervation of Temporalis Muscle:
- Provide motor innervation to the temporalis muscle
- Have articular branches contributing to the innervation of the temporomandibular joint

Course and Distribution of Deep Temporal Nerves:
- Pass superior to the superior border of the lateral pterygoid muscle
- Ascend to the temporal fossa
- Enter the deep surface of the temporalis muscle
- Provide motor innervation to the temporalis muscle
- Have articular branches contributing to the innervation of the temporomandibular joint

Variation in Deep Temporal Nerves:
- Usually two deep temporal nerves (anterior and posterior)
- Occasionally a third deep temporal nerve (middle) may be present
- The anterior deep temporal nerve may arise from the buccal nerve
- The posterior deep temporal nerve may arise from the masseteric nerve

Summary:
The deep temporal nerves arise from the mandibular nerve and pass superior to the superior border of the lateral pterygoid muscle. They then ascend to the temporal fossa and enter the deep surface of the temporalis muscle. These nerves provide motor innervation to the temporalis muscle and have articular branches that contribute to the innervation of the temporomandibular joint. Variations can occur, with usually two deep temporal nerves (anterior and posterior), and occasionally a third deep temporal nerve (middle) may be present. The anterior deep temporal nerve may arise from the buccal nerve, while the posterior deep temporal nerve may arise from the masseteric nerve.