Transverse Foramen

Transverse Foramen The structure indicated is the transverse foramen of a cervical vertebra. There are 33 vertebrae which make up the spinal column: 7 cervical 12 thoracic 5 lumbar 5 fused sacral vertebrae 3-4 fused coccygeal vertebrae The typical vertebra consists of the following features: Vertebral body Vertebral arch (neural arch) consisting of lamina and pedicle Spinous process Transverse process Vertebral foramen (collectively form vertebral canal) Superior and inferior articular processes Superior and inferior vertebral notches Transverse foramina are only present in the cervical vertebrae. These foramina allow the passage of the vertebral artery and vein. The vertebral arteries arise …

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transverse foramen

Internal Carotid Artery

Internal Carotid Artery The structure indicated is the internal carotid artery. The internal carotid arteries arise from the common carotid arteries. The brachiocephalic artery arises from the arch of the aorta and divides into the right subclavian artery and the right common carotid artery. There is no left brachiocephalic artery however, and the left common carotid arises directly from the aortic arch. There are three branches which come off the aortic arch: Brachiocephalic artery Left common carotid Left subclavian The common carotid arteries then divide into the external carotid and internal carotid arteries. The internal carotid artery ascends to supply the …

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internal carotid artery

Vertebral Artery

Vertebral Artery The structure indicated is the vertebral artery. The vertebral arteries arise from the first part of the subclavian artery. Two other arteries are given off from the first part of the subclavian artery – the internal thoracic artery and the thyrocervical trunk. The vertebral and internal carotid arteries provide the arterial supply to the brain, forming the Circle of Willis at the base of the brain. After the vertebral artery is given off from the subclavian artery, it passes through the transverse foramina of cervical vertebrae C1 to C6. It then enters the skull via the foramen magnum. …

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vertebral artery

Carotid Sinus

Carotid Sinus The structure indicated is the carotid sinus. The carotid sinus is located just above the bifurcation of the common carotid artery at the base of the internal carotid artery. The carotid sinus is an important structure in regulating and maintaining blood pressure. It contains baroreceptors which are sensitive to increases in arterial blood pressure and subsequent increased pressure and stretching of the arterial walls. The carotid sinus receives innervation via cranial nerve IX (glossopharyngeal nerve). This nerve synapses in the nucleus tractus solitarii of the medulla oblongata which then indirectly adjusts the level of autonomic outflow and controls …

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Carotid Sinus

Rectus Capitis Posterior Minor

Rectus Capitis Posterior Minor The structure indicated is the rectus capitis posterior minor muscle. The rectus capitis posterior minor is one of 4 muscles which make up the suboccipital group of back muscles. This group of small muscles are located at the base of the occipital bone in the superior cervical region posteriorly. The four suboccipital muscles are: Rectus capitis posterior major Rectus capitis posterior minor Obliquus capitis inferior Obliquus capitis superior Origin:  spinous process of atlas vertebrae CI Insertion: occipital bone inferior to nuchal line Innervation: posterior ramus of CI Action: Extension of head   Learn more about the …

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Rectus Capitis Posterior Minor

Splenius Capitis

Splenius Capitis The structure indicated is the splenius capitis muscle. The splenius capitis muscle is one of 8 muscles in the posterior triangle of the neck. The posterior triangle of the neck is bounded as follows: Anteriorly: posterior border of sternocleidomastoid Posteriorly: anterior border of trapezius Apex: Occipital bone between attachment sites of trapezius and sternocleidmastoid Base: middle third of clavicle Origin: Lower half of ligamentum nuchae and spinous processes of C7-T4 Insertion: Mastoid process, and part of skull inferior to lateral superior nuchal line. Action: Contraction together – extension of the neck. Contraction individually – Lateral flexion of neck …

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Splenius Capitis

Internal Jugular Vein

Internal Jugular Vein The structure indicated is the internal jugular vein. The jugular veins are responsible for returning deoxygenated blood from the head to the heart via the superior vena cava. There are two jugular veins: External jugular vein Internal jugular vein The external jugular vein drains into the subclavian vein. The internal jugular vein joins the subclavian vein to form the brachiocephalic vein. The brachiocephalic veins (innominate vein) on either side then join one another to form the superior vena cava, to bring blood into the right atrium of the heart. The external jugular vein runs superficial to the …

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Internal Jugular Vein


Omohyoid The structure indicated is the omohyoid muscle. The omohyoid muscle is one of four infrahyoid muscles which lie in the anterior triangle of the neck. The infrahyoid muscles, as the name suggests, attach to the hyoid bone and lie below it. Contraction of the infrahyoid muscles then causes depression of the hyoid bone. The infrahyoid muscles are often referred to as the strap muscles due to their strap-like appearance. The four infrahyoid muscles are: Omohyoid Sternohyoid Thyrohyoid Sternothyroid The omohyoid muscle sits lateral to the sternohyoid muscle and is comprised of two muscle bellies (superior and inferior) connected by …

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Omohyoid Muscle

Isthmus of Thyroid Gland

Isthmus of Thyroid Gland The structure indicated is the isthmus of the thyroid gland. The thyroid gland sits anteriorly in the neck, just inferior to the thyroid cartilage. It is located deep to the overlying strap muscles (sternohyoid, sternothyroid and omohyoid). It has two lateral lobes connected in the centre by the isthmus. The isthmus lies over the 2nd and 3rd rings of the trachea The lateral lobes extend from the lateral aspects of the thyroid cartilage down as far the 6th ring of the trachea. Occasionally a pyramidal lobe is present, which is an upward extension of the isthmus, …

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Isthmus of Thyroid Gland