Anatomy of the Head and Neck lecture 1 Abbas A. A. Shawka Medical student 2 nd stage

Subjects  Introduction 1  Head components  Neck components  Triangles of neck

Introduction In these lectures we will study the anatomy of H&N. The head and neck are anatomically complex areas of the body. You will have fun in studying anatomy in this way !

Head components The head is composed of a series of compartments, which are formed by bone and soft tissues. They are: 1.the cranial cavity, 2.two ears, 3.two orbits, 4.two nasal cavities, and 5.an oral cavity

Cranial cavity The cranial cavity is the largest compartment and contains the brain and associated membranes (meninges). Most of the ear apparatus on each side is contained within one of the bones forming the floor of the cranial cavity. The external parts of the ears extend laterally from these regions. Simply, it Composed of a roof and floor. Roof Floor

Orbits The two orbits contain the eyes. They are cone-shaped chambers immediately inferior to the anterior aspect of the cranial cavity, and the apex of each cone is directed posteromedially. The walls of the orbits are bone, whereas the base of each chamber can be opened and closed by the eyelids.

Nasal cavity The nasal cavities are the upper parts of the respiratory tract and are between the orbits. They have walls, floors, and ceilings, which are predominantly composed of bone and cartilage. The anterior openings to the nasal cavities are nares (nostrils), and the posterior openings are choanae (posterior nasal apertures). Continuous with the nasal cavities are air-filled extensions (paranasal sinuses) ( arrowed ), which project laterally, superiorly, and posteriorly into surrounding bones. The largest, the maxillary sinuses, are inferior to the orbits. nostrils conchae

Oral cavity The oral cavity is inferior to the nasal cavities, and separated from them by the hard and soft palates. The floor of the oral cavity is formed entirely of soft tissues. The anterior opening to the oral cavity is the oral fissure (mouth), and the posterior opening is the oropharyngeal isthmus. Unlike the nares and choanae, which are continuously open, both the oral fissure and oropharyngeal isthmus can be opened and closed by surrounding soft tissues. Hard palate Soft palate

Other compartments In addition to these five compartments there is also four areas. Two of them related to a transitional areas which are: 1.infratemporal fossa 2.pterygopalatine fossa The other two related to the surface anatomy of the head which are : 1.the scalp 2.The face

infratemporal fossa The infratemporal fossa is an area between the posterior aspect (ramus) of the mandible and a flat region of bone (lateral plate of the pterygoid process) just posterior to the upper jaw (maxilla). This fossa, bounded by bone and soft tissues, is a conduit for one of the major cranial nerves-the mandibular nerve (the mandibular division of the trigeminal nerve [V3] ), which passes between the cranial and oral cavities.

Infratemporal fossa

pterygopalatine fossa The pterygopalatine fossa on each side is just posterior to the upper jaw. This small fossa communicates with the cranial cavity, the infratemporal fossa, the orbit, the nasal cavity, and the oral cavity. A major structure passing through the pterygopalatine fossa is the maxillary nerve (the maxillary division o f the trigeminal nerve [ V 2 ] ).

Face and scalp The face is the anterior aspect of the head and contains a unique group of muscles that move the skin relative to underlying bone and control the anterior openings to the orbits and oral cavity. The scalp covers the superior, posterior, and lateral regions of the head Scalp face

The Neck Its superior boundary is along the inferior margins of the mandible and bone features on the posterior aspect of the skull. The posterior neck is higher than the anterior neck to connect cervical viscera with the posterior openings of the nasal and oral cavities. The inferior boundary of the neck extends from the top of the sternum, along the clavicle, and onto the adjacent acromion, a bony projection of the scapula. Posteriorly, the inferior limit of the neck is less well defined, but can be approximated by a line between the acromion and the spinous process of vertebra C7, which is prominent and easily palpable. The inferior border of the neck encloses the base of the neck.

Neck compartments 1.The vertebral compartment contains the cervical vertebrae and associated postural muscles. 2.The visceral compartment contains important glands (thyroid, parathyroid, and thymus), and parts of the respiratory and digestive tracts that pass between the head and thorax. 3.The two vascular compartments, one on each side, contain the maj or blood vessels and the vagus nerve. These four compartments are enclosed by musculofascial collar

Triangles of Neck The two muscles (trapezius and sternocleidomastoid) that form part of the outer cervical collar divide the neck into anterior and posterior triangles on each side. The boundaries of each anterior triangle are: 1.the median vertical line of the neck, 2.the inferior margin of the mandible, and 3.the anterior margin of the sternocleidomastoid muscle. The posterior triangle is bounded by: 1.the middle one-third of the clavicle, 2.the anterior margin of the trapezius, and 3.the posterior margin of the sternocleidomastoid. Posterior Posterior T. Anterior Anterior T.